vue3

# vue3

# setup

setup：新的 option，所有的组合 API 函数都在此使用

Hello vue3

<div class="hello">{{ msg }}</div>
<el-button @click="log('props')">props</el-button>
<el-button @click="log('context')">context</el-button>
<el-button @click="log('context')">instance</el-button>
<script>
    import { defineComponent ,toRefs, getCurrentInstance } from 'vue'
    export default defineComponent({
        props: {
            title: {
                type: String,
                default: "vue3",
            },
        },
        setup(props, context) {
            //组合api入口函数，只会触发一次
            //如果返回对象，可以在模板中使用
            //无法访问data、computed、methods、模板refs
            const msg= "Hello vue3";
            const {attrs} =context//包括attrs、emit、slots属性
            //console.log(props.title)
            const { title } = toRefs(props)//使用toRefs解构保持响应性
            //没有this,可以通过getCurrentInstance获取实例
            const instance= getCurrentInstance()//VueComponent
            const log=(type)=>{
                console.log(eval(type))
            }
            return { msg,log };
        },
    })
</script>

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setup script语法糖

<div>
    <input @input="change($event)" :value="user" />
    {{user}}
</div>
<script lang="ts" setup>
    import { ref, useSlots, defineProps, useAttrs } from "vue";  
    //defineEmit,defineProps,defineExpose定义属性、事件...,useContext弃用
    const user = ref("小明");//不需要return
    function change(e: Event) {
        user = e.target.value;
    }
    const solt:Object =useSlots()//获取插槽
    console.log(solt.default())
    console.log(useAttrs())//获取属性与事件
</script>

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defineExpose

<script setup lang="ts">
//子组件
const method=()=>{}
//使用 <script setup> 的组件是默认关闭的,不会暴露任何在 <script setup> 中声明的绑定。
defineExpose({
  method
})

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# 响应式

ref：定义一个基本类型响应式数据

<div>
    {{ count }}
    <el-button @click="count++">加1</el-button>
    <!-- 模板中不需使用.value写法 -->
    <el-button @click="add">加1</el-button>
</div>
<script>
    import { ref } from "vue";
    export default {
        name: "hello",
        setup() {
            let a = 0; //此时a不是响应式的
            let count = ref(a);//依然是靠object.defineProperty()的get与set完成的
            function add() {
                count.value++;// 通过xxx.value操作数据
            }
            return {
                count,
                add,
            }
        }
    }
</script>

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reactive:接收普通对象，返回该对象的响应式代理对象

Tom is 18

性别：

<div>
    {{ `${user.name} is ${user.age}` }}
    <p>性别：{{ user.sex }}</p>
<el-button @click="update">更新数据</el-button>
</div>
<script>
    import { ref, reactive } from "vue";
    export default {
        name: "hello",
        setup() {
            const obj= {
                name: "Tom",
                age: 18,
            };
            let user = reactive(obj);//使用Proxy来实现响应式（数据劫持）, 并通过Reflect操作源对象内部的数据。
            //返回Proxy代理对象
            function update() {
                user.name = "牛夫人"
                user.age=19
                user.sex = "女"
                //需要使用代理对象更新属性值
            }
            return { user,update }
        },
    }
</script>

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toRef

<template>
  {{ refCount }}
</template>

<script setup lang="ts">
import { reactive, toRef } from "vue";
const state = reactive({
  count: 1,
})
const refCount = toRef(state, 'count')//转换单个属性
refCount.value++
</script>

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toRefs

HcySunYang

Vue.js设计与实现

<template>
<div>
    <img :src="img" style='width:100px'/>
    <p>{{ author }}</p>
    <p>{{ name }}</p>
    </div>
<div id="ipt"></div>
</template>
<script>
    import { toRefs, reactive, h, nextTick, onMounted } from "vue";
    export default {
        setup() {
            const book = reactive({
                author: "HcySunYang",
                name: "Vue.js设计与实现",
                img: "https://img3.jarhu.com/goodimg/202202/151/di1644900399702.jpg",
            });
            //直接解构并不是响应式的
            let { author, name, img } = toRefs(book); //toRefs保持响应式
            const render = h("input", {
                value: name.value,
                onInput: e => {
                    name.value = e.target.value;
                },
            });
            return { author, name, img };
        },
    };
</script>

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readonly

<script setup lang="ts">
    import { ref, readonly } from "vue";

    const state = readonly<{
        msg: string
    }>({ msg: '123' })
    state.msg='12122'//接受一个对象 (不论是响应式还是一般的) 或是一个 ref，只读属性无法修改
</script>

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# 进阶

customRef()

# 生命周期钩子

在生命周期钩子前面加上 “on” 来访问组件的生命周期钩子。

<script>
import { defineComponent,onMounted } from 'vue'

export default defineComponent({
  setup() {
    onMounted(()=>{
      // console.log('Component is mounted!')
    })
  },
})
</script>

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# 计算属性

从 Vue 导入的 computed 函数
可写的计算属性

# 侦听器

watch

<script setup lang="ts">
    import { ref, watch, watchEffect } from 'vue'
    const count = ref(0)
    //依赖源，回调，配置
    const unwatch = watch(count, (n, o) => {
        console.log(n)
    },{
        deep: false,//深层侦听器
        immediate: true,
        flush: 'post'//Vue 更新之后的DOM
    })
</script>

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watchEffect

<script setup lang="ts">
import { ref, watch, watchEffect } from 'vue'
const age = ref(18)
const name = ref('zs')
age.value++
const unwatch = watchEffect(() => {
  console.log(age.value, name.value)//立即执行，不需要指定状态,追踪多个依赖
})
</script>

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# 组件传值

prop/emit

<template>
<!-- 父组件 -->
<Son :msg='msg' @change='change' />
</template>

<script setup lang="ts">
    import { ref } from 'vue'
    import Son from './components/Son.vue'
    const msg = ref('msg')
    const change = (param: string) => {
        console.log(param)
    }
</script>

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<script setup lang="ts">
    //子组件
    import { defineProps, defineEmits, toRefs } from 'vue'
    const props = defineProps(['msg'])
    const { msg } = toRefs(props)
    console.log(msg.value)
    const emits = defineEmits(['change'])
    emits('change', 'son message')
</script>

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provide/inject

<script setup lang="ts">
    //祖先组件
    import { ref, provide } from 'vue'
    import Son from './components/Son.vue'
    const name = ref('name')
    const age = ref(18)
    provide('info', {
        name,age
    })
</script>

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<script setup lang="ts">
    //后代组件
    import { inject } from 'vue'
    const info = inject('info')
    console.log(info)
</script>

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attrs/listeners

<template>
<!-- 父组件 -->
<Son @fun='fun' :msg='msg' />
</template>

<script setup lang="ts">
    import Son from './components/Son.vue'
    import { ref, provide } from 'vue'
    const msg = ref('message')
    const fun = () => {
        console.log('fun')
    }
</script>

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<script setup lang="ts">
    //子组件
    import { useAttrs } from 'vue'
    const attrs: any = useAttrs()//获取传来的属性和v-on事件监听器
    console.log(attrs)//Proxy {onFun: ƒ, msg: "message"}
    const { onFun, msg } = attrs//自定义事件有on前缀
    onFun()
</script>

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solt

<template>
<!--子组件传递数据-->  
<slot name="son" msg="son data">default</slot>
</template>

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<template>
<!--父组件使用一个变量接收-->  
<Son v-slot:son="data">
    {{ data.msg }}
    </Son>
</template>

<script setup lang='ts'>
    import Son from './components/Son.vue'
</script>

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expose/ref

<script lang="ts" setup>
    //子组件使用defineExpose暴露属性
    import { ref,defineExpose } from 'vue'
    const a = ref(1)
    const b = ref(2)
    defineExpose({
        a,
        b
    })
</script>

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<template>
  <Son ref="son" />
</template>

<script setup lang='ts'>
import Son from './components/Son.vue'
import { nextTick } from 'vue';

const son = ref(null)
nextTick(() => {
  console.log(son.value)
})
</script>

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EventBus/mitt

# 渲染函数 & JSX

函数式组件

# 模板引用

ref

demo

<template> 
<el-button @click='getEl'>ref</el-button>
<div ref="demo">demo</div>
</template>

<script>
    import { ref } from 'vue'
    export default{
        setup(){
            const demo = ref(null)// DOM 元素将在初始渲染后分配给 ref
            const getEl = ()=> console.log(demo.value)
            return { demo, getEl }
        }
    }

</script>

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# 指令

# pinia (opens new window)

安装

import { createPinia } from 'pinia'
import piniaPluginPersist from 'pinia-plugin-persist'
const pinia = createPinia()
pinia.use(piniaPluginPersist)//使用数据缓存
import App from './App.vue'
const app = createApp(App)
app.use(pinia)

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定义容器&&数据持久化

//定义导出容器
//store/index.ts
import { defineStore } from 'pinia'
export const useMainStore = defineStore('main', {//容器id必须唯一，pinia会把容器挂载到根容器
    state: () => {//类似data1.必须是函数：避免服务端渲染数据污染2.必须是箭头函数：更好的TS类型推导
        return { count: 0, name: '星野梦美',arr:[1,2,3] }
    },
    getters: {//有缓存功能
        count10(state) {//使用state有类型推导
            return state.count + 10
        },
        //count10(): number {
        //  return this.count + 10
        //}
    },
    actions: {//类似methods，不能使用箭头函数，this指向变了
        increment() {
            this.count++
        },
    },
    // 开启数据缓存
    persist: {
        enabled: true,
        strategies: [
            {
                key:'my_user',//默认容器id作为key
                storage: localStorage,//默认sessionStorage
                paths: ['count', 'name']//缓存字段
            }
        ]
    }
})

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使用

<template>
<p>{{ count }}</p>
<p>{{ name }}</p>
<p>{{ arr }}</p>
<el-button @click="add"> add</el-button>
</template>
<script lang='ts' setup>
    import { useMainStore } from "./store/index";
    const mainStore = useMainStore();
    const { count, name, arr } = storeToRefs(mainStore); //直接解构数据(getters)不是响应式的
    function add() {
        //方式一：直接修改数据
        // mainStore.count++;

        //方式二：修改多个数据
        // mainStore.$patch({//修改多个数据建议使用$patch性能优化
        //   count: mainStore.count+1,
        //   name: "凉宫春日",
        //   arr:[...mainStore.arr,mainStore.arr.length+1]
        // });

        //方式三
        // mainStore.$patch(state => {
        //   state.count++;
        //   state.name = "凉宫春日";
        //   state.arr.push(arr.value.length+1);
        // });

        //方式四:封装action
        mainStore.increment()
    }
</script>

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# 工具

vue-global-api

开始 Electron

Notes

Choose mode

vue3

# vue3

# setup

# 响应式

# 进阶

# 生命周期钩子

# 计算属性

# 侦听器

# 组件传值

# 渲染函数 & JSX

# 模板引用

# 指令

# pinia (opens new window)

# 工具